The referenced U.S. Pat. No. 4,859,899, Keeffe et al, the disclosure of which is hereby incorporated by reference, discloses an improved metal halide arc discharge lamp which has an arc tube having an essentially cylindrical body. A heat conserving sleeve surrounds the arc tube. Both the arc tube and the sleeve are located within an evacuated outer envelope. This lamp has improved performance, both with respect to luminous efficacy as well as color rendering index. The discharge vessel or arc tube is retained within the glass envelope of the lamp by a metal holding frame. The heat conserving, heat retention sleeve has open ends and functions as a heat damming or heat conservation tube. It is retained in position within the lamp by the frame which also supports the arc tube. The heat conserving sleeve is secured to the frame by straps. Placing the straps on the frame and securing the sleeve to the frame, and then the entire assembly in the lamp, is complex and time-consuming in manufacture.